The proposed research will employ nuclear magnetic resonance (NMR) measurements of specifically labeled proteins to obtain details of enzyme conformation and mechanism including the properties of individual amino acid side chains and the consequences of conformational changes which accompany substrate binding, metal ion binding, and subunit interactions. The enzymes to be studied include alpha-lytic protease containing (gamma-13C)-histidine, horse liver alcohol dehydrogenase labeled chemically with 19F or 3H, and various metalloenzymes containing (gamma-13C)-histidine.